Patent GB-756966-A (GB)
Title: Improvements in or relating to composition of matter
IPC: C09C1/30
Filed: 1953-12-02
Abstract: Synthetic rubber compositions comprise the product obtained by heating together an organic isocyanate and finely divided silica having an average particle size below 0.1 micron and containing bound water corresponding to the formula H2O(SiO2)x where x is 3 to 85. The synthetic rubber may be a polymer of butadiene - 1,3, isoprene, piperylene, 2,3-dimethyl butadiene, 2-chlorobutadiene-1,3, or a copolymer of these monomers with acrylonitrile, vinyl chloride, vinyl acetate, styrene, methyl methacrylate, methyl alpha-chloracrylate, methyl acrylate or isobutylene.  The silica may be made from calcium silicate by treatment with hydrochloric acid (see Group III). Examples describe the use of toluene 2,4-diisocyanate, octodecyl isocyanate, phenyl isocyanate, toluene diisocyanate partially reacted with trimethylol propane, tri-p-phenylisocyanate methane, and methylene bis-(4-phenylisocyanate).  The compositions may be vulcanized.  Specification 756,857, [Group III], is referred to.ALSO:A finely divided material which may be used as a filler for natural and synthetic rubber (see Groups IV(a) and V) comprises the product obtained by heating together an organic isocyanate, and finely divided silica having an average particle size below 0.1 micron and containing bound water corresponding to the formula H2O(SiO2)x where x is 3 to 85.  The silica preferably consists of at least 85 per cent.  SiO2, and has a surface area of 25-200 square metres per gram.  The silica is preferably made by reacting calcium silicate with hydrochloric acid although hypochlorous acid, hydrobromic acid, nitric acid, nitrous acid and acetic acid may also be used.  The resulting product may be calcined at about 600 DEG C. In examples the finely divided silica is treated with toluene 2, 4 - diisocyanate, octadecyl isocyanate, phenyl isocyanate, toluene diisocyanate partially reacted with trimethylol propane, tri-pphenylisocyanate methane, or methylene bis (4-phenylisocyanate) dissolved in carbon tetrochloride and then dried at 105 DEG C.  About 0.25 to 20 per cent. by weight of isocyanate based on the silica is normally used.  Specification 756,857 is referred to.ALSO:Natural rubber compositions comprise the product obtained by heating together an organic isocyranate, and finely divided silica having an average particle size below 0.1 micron and containing bound water corresponding to the formula H2O (Si O2)x where x is 3 to 85.  The silica which preferably contains bound water may be made from calcium silicate by treatment with hydrochloric acid as described in Group III.  Many isocyanates are specified and the following are used in examples, toluene 2, 4-diisocyanate, octodecyl isocyanate, phenyl isocyanate, toluene diiscocyanate partially reacted with trimethylol propane, tri-p-phenylisocyanate methane, and methylene bis (4-phenylisocyanate).  In Examples XV and XVI one of the above isocyanates was dissolved in carbon tetrachloride and then the solution slurried with finely divided silica, and then the solvent removed at 105 DEG C.  The treated silica was then added to a mixture consisting of natural rubber, zinc oxide, sulphur, stearic acid, agerite powder, diorthotol guanidine and benzothiazyl dissulphide. Specification 756,857 [Group III] is referred to.